This invention is concerned with parison transferring means for use in transferring glass parisons from a parison forming mould of a glassware manufacturing machine to a further mould of the machine in which the parison is formed into an article of glassware or to further transferring means operable to transfer the parison to the further mould.
Glassware manufacturing machines of the standard "individual section" type are equipped with parison transferring means which operates after a parison has been formed in a parison forming mould, from a gob of molten glass by either a pressing or a blowing operation. The parison transferring means operates to transfer the parison to a further mould in which the parison is formed into an article of glassware by a blowing operation. Some machines of the individual section type have an intermediate station at which the parison is re-heated and/or partially formed before transfer to the further mould. In this type of machine, the parison transferring means transfers the parison to further transferring means operable to transfer the parison to the further mould after re-heating and/or partial forming.
The parison transferring means of a conventional machine comprises a shaft mounted on a supporting frame of the machine for turning movement about a horizontal longitudinal axis of the shaft arranged between the parison forming mould and the further mould. Two neck ring supports are mounted on the shaft to turn therewith and for sliding movement along the shaft towards or away from one another. The transferring means also comprises moving means, in the form of pneumatically-operated piston and cylinder assemblies with spring-return, operable to move the neck ring supports towards or away from one another as aforesaid. Thus, one or more split neck rings, half of each ring being supported by each support, can be moved between gripping and releasing conditions in which they can grip or release parisons.
The parison transferring means of a conventional machine also comprises turning means operable to turn the shaft back and forth along an arc about the horizontal axis. The turning movement is through approximately 180.degree. between a position at which a neck ring supported by the supports is beneath a parison forming mould of the machine and a position at which the neck ring can release a parison into the further mould or into the further transferring mould. While the neck ring is beneath the parison forming mould, the neck ring cooperates with the mould in forming the parison which is gripped by the neck ring, portions of the mould then separate to allow the neck ring to pass between them as the turning means operates. After the parison has been released, the turning means operates to move the neck ring in the opposite direction along the arc to return the neck ring to beneath the parison forming mould to grip the next parison formed in the mould.
The turning means of the parison transferring means of a conventional machine comprises a vertically-disposed piston and cylinder assembly operable to move a vertically-extending piston rod. A toothed rack is mounted on the piston rod and meshes with a gear formed on the shaft. The arrangement is such that vertical movement of the piston of the assembly moves the toothed rack vertically turning the gear and thereby moving the neck ring. The end positions of the movement of the neck ring have to be precisely adjusted so that the neck ring cooperates correctly with the parison forming mould and with the further mould. This adjustment is made by moving adjustable stops which are mounted on end caps of the cylinder of the assembly to project into the cylinder and engage the piston so that the adjustment of the stops controls the rest positions of the piston and hence of the neck ring. However, as the cylinder is mounted within a supporting frame these stops are inaccessible and, furthermore, the precision of the adjustment may be affected by backlash between the rack and the gear which occurs between the stops and the neck ring.
It is an object of the present invention to provide parison transferring means in which the end positions of the movement along the arc are determined by adjustable stops which are accessible and the precision of the adjustment is not affected by backlash.